Multi-institution longitudinal apparent diffusion coefficient measurements in a diffusion weighted imaging phantom at room temperature.

Moore, C.; Bull, C.; Darekar, A.; Wilson, D.; Goodall, A.; Manoharan, P.; Hoskin, P.; van Herk, M.; Buckley, DL.; McHugh, DJ.; Datta, A.; Dubec, MJ.

Multi-institution longitudinal apparent diffusion coefficient measurements in a diffusion weighted imaging phantom at room temperature.

All Authors

Moore, C.

Bull, C.

Darekar, A.

Wilson, D.

Goodall, A.

Manoharan, P.

Hoskin, P.

van Herk, M.

Buckley, DL.

McHugh, DJ.

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LTHT Author

Wilson, Daniel

LTHT Department

Oncology
Medical Physics & Engineering

Non Medic

Clinical Scientist

Publication Date

2025

Item Type

Journal Article

Abstract

Background and purpose: This work contributes to technical validation of apparent diffusion coefficient (ADC) as a biomarker of cancer. The aim was to evaluate ADC accuracy, random error, short-term and long-term repeatability and reproducibility, across multiple institutions using a room temperature phantom. Materials and methods: ADC measurements were made in a travelling room temperature diffusion weighted imaging (DWI) phantom on six scanners at four UK institutions over 18 months at six-month intervals. ADC bias measurements were calculated as the difference between measured and temperature corrected ground-truth ADC values and used to calculate mean ADC bias, isocentre ADC error estimate, short- and long-term intra-scanner repeatability as per the Quantitative Imaging Biomarkers Alliance (QIBA) DWI profiles, and inter-scanner reproducibility by calculating the 95 % limits of agreement for all ADC bias measurements. Results: The use of a room-temperature phantom with a magnetic resonance (MR) readable thermometer enabled ADC measurements without ice-water setup, considerably simplifying logistics with respect to multi-institution ADC quality assurance. Mean ADC bias across all scanners and sessions was <0.01 x 10-3 mm2 s-1 (0.81 %); mean isocentre ADC error estimate was 1.43 %; average scanner short-term repeatability was <0.01 x 10-3 mm2 s-1 (1 %). Reproducibility was 0.07 x 10-3 mm2 s-1 (9 %). Conclusion: Results indicated good ADC accuracy, repeatability and reproducibility; demonstrating the feasibility of transferring diagnostic DWI sequences between scanners from the same manufacturer, for use in multi-institution longitudinal studies, and assessing ADC with minimal quality control and harmonisation steps required.